Electrochemically, a fuel cell converts a raw fuel into electrical energy and heat and will continue the production as long as raw fuel is being continuously supplied.
The basic conversion technology of fuel cells is well known for at least a century but has come into a renaissance with the latest development and demands for fuel saving and environmental friendly technology. Additionally fuel cell technology is advantageous for electrical supply on mobile or remote platforms and for backup solutions.
Briefly explained, using the protone exchange membrane technology, a fuel cell needs a supply of hydrogen to be passed along a first electrode, forming the anode, and a supply of oxygen, typically taken directly as atmospheric air, to be passed along a second electrode, forming the cathode. Arranged between the electrodes is an ion-conducting layer, typically a polymer film comprising platine and phosphoric acid. Supplying the hydrogen and oxygen, generates an electrical voltage between the electrodes and a current will be able to flow between the electrodes and supply an attached electrical consumer. Corresponding to the draw of current, a number of hydrogen and oxygen molecules will react, and later when combined in the exhaust the hydrogen ions and oxygen will form water as the end product. Additionally the system will generate heat.
Since the necessary oxygen supply is achieved by taking in sufficient amounts of oxygen containing atmospheric air, the overall need for utilizing a fuel cell is to form a steady and sufficient supply of hydrogen. Supplying hydrogen can possibly be from pressurized cylinders, small or large, but the distribution and storage is critical since hydrogen is a highly explosive gas. Pressurizing hydrogen is quite energy consuming and even in pressurized form hydrogen takes up relatively much space. A better solution is to generate hydrogen directly on the spot by conversion of more stable forms of fuel into a synthetic gas containing high amounts of hydrogen, hereafter called a syngas.
Appreciated is the process of using methanol for producing the hydrogen containing syngas for the obvious advantages when it comes to distribution. The technology describe both low and high temperature fuel cell stacks where a temperature of 120 degrees celsius is the temperature for which the split between the technologies is commonly understood. More specifically a low temperature system commonly works in the temperature area around 70 degrees Celsuis and the high temperature system at around 160 degrees Celsius. However, for both technologies apply that the process requires a reformer, for processing the fuel and supplying a syngas containing free hydrogen. The fuel processed is methanol in an aquatic solution, hereafter referenced as liquid fuel. In a first stage, a heater evaporates the liquid fuel and the gas is forwarded to the reformer. The reformer includes a catalyst including copper, which in addition to heat converts the liquid fuel into a syngas mainly consisting of hydrogen with a relatively large content of carbon dioxide and a small content of water mist and carbon monoxide. The syngas is directly useable as a fuel supply for supplying the fuel cell.
For an effective operation of the reformer, the state of art suggests the reformer to be arranged as an upright standing entity, such that the incoming gas cannot escape without interaction with the reformer catalyst and be reformed to the appreciated syngas. This design manner is though a challenge when the wish is to build a fuel cell system that is more compact and preferably is designed as an exchangeable rack unit with the obvious advantages.
Thus, there is a need for an improvement of the design of the reformer in order to achieve a more compact design. There is also a need for an improved design of the reformer, which in a more reliable way secures that the full amount of supplied gas mixture, delivered by the evaporator, is reformed into syngas.